Machine for refining paper stock



NOV. 5, 1940. CQWLES 2,220,677

MACHINE FOR REFINING PAPER STOCK Filed \Sept. 16, 1957 um-m-m-muw-u' l9 Y: rmya'rlon I ATTORNEY Patented Nov. 5, 1940 PATENT OFFICE MACHINE FOR REFINING PAPER STOCK Edwin Cowles, Hopewell, N. J., assignor to The Cowles Company, Princeton, N. J., a corporation of New Jersey I Application September 16, 1937, Serial No. 164,104

1 Claim.

This invention relates to machines for refining paper stock and pertains more particularly to machines of the type disclosed in my United States Patent Nos. 2,033,123 and 2,180,080 and my copending application Serial No. 121,837, filed January 22, 1937. Y f

It is an object of the present invention to pro.- vide improved scrapers for attachment to the impeller vanes of such machines to improve the refining action thereof, and to'enable the various types of refining action required in the treatment of various types of stock to be performed most efficiently.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention selected for purposes of illustration is shown in the accompanying drawing, in which,

Figure 1 is a vertical cross section through one form of scraper embodying my invention.

Figure 2 is a front elevation of the same.

Figure 3 is a vertical cross section through a another modified form of scraper.

Figure 6 is a front elevation of the same.

Figure '7 is a vertical cross section through another modified form of scraper.

Figure 8 is a front elevation of the same.

Inasmuch as the patent and applications above referred to provide disclosures of the machines as a whole, the drawing herein is limited to the details of the scrapers forming the subject matter of the invention. Referring to the drawing, the impeller vane is indicated by the numeral I and the perforated screen is indicated by the numeral 2.

Refening now to Figures 1 and 2, a scraper is illustrated having a surface 3 extending 'substantially parallelv to the screen 2 and having another surface 4 inclined with respect to the screen, said surfaces intersecting at an acute angle to form a fiber engaging edge 5 extending parallel to the screen. The said scraper is provided with an upstanding flange 6 for attachment to the impeller vane as by means of bolt 1. The aperture 8 through which the bolt passes is elongated vertically in order to permit the scraper to be adjusted with respect to the screen. Thus the scraper may be adjusted to contact with the screen, or it maybe adjusted to move a short distance above the screen.

In Figures 3 and 4, a similar type of scraper is illustrated, in that the surface 9 and the sura spring to hold the foot in contact with the screen 2. The tension exerted by the yielding web may be adjusted, of course, by adjusting the position of the flange 6 with respect to the impeller vane.

While. thescraper illustrated in Figures 1 and 2 is generally similar to that illustrated in Figures 3 and 4, the refining action obtained is considerably difierent, for whereas the action in the former is mainly a rubbing action on the fibers, due to their tendency to staple over the advancing edge of the scraper, thus forming a pad, the action in the latter is mainly a cutting action. However, the results obtained depend'somewhat on the adjustment of the scrapers on the vanes.

For example, the closer the scraper of Figures 1 and 2 is'adjusted to the screen the more cutting and the less rubbing will result. Likewise, the greater the tension exerted by the web I! in the scraper of Figures 3 and 4 the more cutting and the less rubbing will result; but if the tension is relaxed the cutting decreases and the rubbing increases. 4

In Figures 5 and 6 a somewhat different type of scraper is illustrated in which the surface I3 and the surface 14 intersect at an obtuse angle to form the fiber engaging edge l5. In this form of scraper the foot is also connected to the flange by means of a yielding web I6. With this type of scraper the predominant result is a bruising action on the fibers due to the impact of the scraper against fibers which may be lodged in the screen perforations, but in some cases, a rubbing action and a cuttingaction may also be observed. 4

In Figures 7 and '8, the scraper illustrated is generally similar to that of Figures 5 and 6, except that it is rigidly secured to the impeller vane. Here again the surface I! and the surface l8 intersect at an obtuse angle to form the fiber engaging edge l9, but this angle is somewhat greater than before. With this. form of scrapera crushing action is the predominating result.

In connection with the scrapers illustrated in Figures 3, 4, 5 and 6 employing the yielding web, it may be advisable to provide the abutments 20 which serve to prevent breakage of the scrapers incase they tend to be. forced upwardly by accumulations of fibers or trash which may be present in the machine.

Each 'of thescrapers is, preferably provided with an inlay 2| of extremely hard metal lying immediately adjacent the inclined surface of the scraper is formed, so that in use, the softer metal opposite the screen is worn away by abrasion, leaving a relatively small area of hardened metal opposite the screen for work against the fibers. Due to the relatively. small area of hardened metal working against the fibers, the effectiveness of the scrapers is greatly increased. Fur- 20 thermore, the scrapers are self-sharpening, 'in

effect, and maintain sharp edges for long periods of time.

It will be understood that the invention may be variously modified and embodied within the .scope of the subjoined claim.

I claim as my invention:

In a machine for refining paper stockhaving a perforated screen and an impeller adapted to move along said screen, a metal scraper mounted on said impeller, said scraper having a surface extending substantially parallel to said screen, and a surface inclined with respect to the screen, said surfaces intersecting at an-acute angle to form a fiber engaging edge, said scraper having a portion formed of hardened metal lying adja-.

cent said inclined surface and extending to said fiber engaging edge, said parallel surface being composed partially of said hardened metal and partially of softer metal.

EDWIN COWLES. 

